// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_AURA_WINDOW_TREE_HOST_H_
#define UI_AURA_WINDOW_TREE_HOST_H_

#include <vector>

#include "base/event_types.h"
#include "base/macros.h"
#include "base/message_loop/message_loop.h"
#include "ui/aura/aura_export.h"
#include "ui/base/cursor/cursor.h"
#include "ui/base/ime/input_method_delegate.h"
#include "ui/events/event_source.h"
#include "ui/gfx/geometry/insets.h"
#include "ui/gfx/native_widget_types.h"

namespace gfx {
class Insets;
class Point;
class Rect;
class Size;
class Transform;
}

namespace ui {
class Compositor;
class EventProcessor;
class InputMethod;
class ViewProp;
}

namespace aura {
namespace test {
    class WindowTreeHostTestApi;
}

class WindowEventDispatcher;
class WindowTreeHostObserver;

// WindowTreeHost bridges between a native window and the embedded RootWindow.
// It provides the accelerated widget and maps events from the native os to
// aura.
class AURA_EXPORT WindowTreeHost : public ui::internal::InputMethodDelegate,
                                   public ui::EventSource {
public:
    ~WindowTreeHost() override;

    // Creates a new WindowTreeHost. The caller owns the returned value.
    static WindowTreeHost* Create(const gfx::Rect& bounds);

    // Returns the WindowTreeHost for the specified accelerated widget, or NULL
    // if there is none associated.
    static WindowTreeHost* GetForAcceleratedWidget(gfx::AcceleratedWidget widget);

    void InitHost();

    void InitCompositor();

    void AddObserver(WindowTreeHostObserver* observer);
    void RemoveObserver(WindowTreeHostObserver* observer);

    Window* window() { return window_; }
    const Window* window() const { return window_; }

    ui::EventProcessor* event_processor();

    WindowEventDispatcher* dispatcher()
    {
        return const_cast<WindowEventDispatcher*>(
            const_cast<const WindowTreeHost*>(this)->dispatcher());
    }
    const WindowEventDispatcher* dispatcher() const { return dispatcher_.get(); }

    ui::Compositor* compositor() { return compositor_.get(); }

    // Gets/Sets the root window's transform.
    virtual gfx::Transform GetRootTransform() const;
    virtual void SetRootTransform(const gfx::Transform& transform);
    virtual gfx::Transform GetInverseRootTransform() const;

    // Sets padding applied to the output surface. The output surface is sized to
    // to the size of the host plus output surface padding. |window()| is offset
    // by |padding|, that is, |window|'s origin is set to padding.left(),
    // padding.top().
    // This does not impact the bounds as returned from GetBounds(), only the
    // output surface size and location of window(). Additionally window() is
    // sized to the size set by bounds (more specifically the size passed to
    // OnHostResized()), but the location of window() is set to that of
    // |padding|.
    void SetOutputSurfacePadding(const gfx::Insets& padding);

    // Updates the root window's size using |host_size|, current
    // transform and outsets.
    virtual void UpdateRootWindowSize(const gfx::Size& host_size);

    // Converts |point| from the root window's coordinate system to native
    // screen's.
    void ConvertPointToNativeScreen(gfx::Point* point) const;

    // Converts |point| from native screen coordinate system to the root window's.
    void ConvertPointFromNativeScreen(gfx::Point* point) const;

    // Converts |point| from the root window's coordinate system to the
    // host window's.
    void ConvertPointToHost(gfx::Point* point) const;

    // Converts |point| from the host window's coordinate system to the
    // root window's.
    void ConvertPointFromHost(gfx::Point* point) const;

    // Cursor.
    // Sets the currently-displayed cursor. If the cursor was previously hidden
    // via ShowCursor(false), it will remain hidden until ShowCursor(true) is
    // called, at which point the cursor that was last set via SetCursor() will be
    // used.
    void SetCursor(gfx::NativeCursor cursor);

    // Invoked when the cursor's visibility has changed.
    void OnCursorVisibilityChanged(bool visible);

    // Moves the cursor to the specified location relative to the root window.
    void MoveCursorTo(const gfx::Point& location);

    // Moves the cursor to the |host_location| given in host coordinates.
    void MoveCursorToHostLocation(const gfx::Point& host_location);

    gfx::NativeCursor last_cursor() const { return last_cursor_; }

    // Gets the InputMethod instance, if NULL, creates & owns it.
    ui::InputMethod* GetInputMethod();

    // Sets a shared unowned InputMethod. This is used when there is a singleton
    // InputMethod shared between multiple WindowTreeHost instances.
    //
    // This is used for Ash only. There are 2 reasons:
    // 1) ChromeOS virtual keyboard needs to receive ShowImeIfNeeded notification
    // from InputMethod. Multiple InputMethod instances makes it hard to
    // register/unregister the observer for that notification.
    // 2) For Ozone, there is no native focus state for the root window and
    // WindowTreeHost. See DrmWindowHost::CanDispatchEvent, the key events always
    // goes to the primary WindowTreeHost. And after InputMethod processed the key
    // event and continue dispatching it, WindowTargeter::FindTargetForEvent may
    // re-dispatch it to a different WindowTreeHost. So the singleton InputMethod
    // can make sure the correct InputMethod instance processes the key event no
    // matter which WindowTreeHost is the target for event. Please refer to the
    // test: ExtendedDesktopTest.KeyEventsOnLockScreen.
    //
    // TODO(shuchen): remove this method after above reasons become invalid.
    // A possible solution is to make sure DrmWindowHost can find the correct
    // WindowTreeHost to dispatch events.
    void SetSharedInputMethod(ui::InputMethod* input_method);

    // Overridden from ui::internal::InputMethodDelegate:
    ui::EventDispatchDetails DispatchKeyEventPostIME(
        ui::KeyEvent* event) override;

    // Returns the EventSource responsible for dispatching events to the window
    // tree.
    virtual ui::EventSource* GetEventSource() = 0;

    // Returns the accelerated widget.
    virtual gfx::AcceleratedWidget GetAcceleratedWidget() = 0;

    // Shows the WindowTreeHost.
    void Show();

    // Hides the WindowTreeHost.
    void Hide();

    // Gets/Sets the size of the WindowTreeHost (in pixels).
    virtual gfx::Rect GetBounds() const = 0;
    virtual void SetBounds(const gfx::Rect& bounds_in_pixels) = 0;

    // Sets the OS capture to the root window.
    virtual void SetCapture() = 0;

    // Releases OS capture of the root window.
    virtual void ReleaseCapture() = 0;

protected:
    friend class TestScreen; // TODO(beng): see if we can remove/consolidate.

    WindowTreeHost();
    void DestroyCompositor();
    void DestroyDispatcher();

    void CreateCompositor();
    void OnAcceleratedWidgetAvailable();

    // Returns the location of the RootWindow on native screen.
    virtual gfx::Point GetLocationOnNativeScreen() const = 0;

    void OnHostMoved(const gfx::Point& new_location);
    void OnHostResized(const gfx::Size& new_size);
    void OnHostCloseRequested();
    void OnHostActivated();
    void OnHostLostWindowCapture();

    // Sets the currently displayed cursor.
    virtual void SetCursorNative(gfx::NativeCursor cursor) = 0;

    // Moves the cursor to the specified location relative to the root window.
    virtual void MoveCursorToNative(const gfx::Point& location) = 0;

    // kCalled when the cursor visibility has changed.
    virtual void OnCursorVisibilityChangedNative(bool show) = 0;

    // Shows the WindowTreeHost.
    virtual void ShowImpl() = 0;

    // Hides the WindowTreeHost.
    virtual void HideImpl() = 0;

    // Overridden from ui::EventSource:
    ui::EventProcessor* GetEventProcessor() override;

private:
    friend class test::WindowTreeHostTestApi;

    // Moves the cursor to the specified location. This method is internally used
    // by MoveCursorTo() and MoveCursorToHostLocation().
    void MoveCursorToInternal(const gfx::Point& root_location,
        const gfx::Point& host_location);

    // We don't use a scoped_ptr for |window_| since we need this ptr to be valid
    // during its deletion. (Window's dtor notifies observers that may attempt to
    // reach back up to access this object which will be valid until the end of
    // the dtor).
    Window* window_; // Owning.

    base::ObserverList<WindowTreeHostObserver> observers_;

    scoped_ptr<WindowEventDispatcher> dispatcher_;

    scoped_ptr<ui::Compositor> compositor_;

    // Last cursor set.  Used for testing.
    gfx::NativeCursor last_cursor_;
    gfx::Point last_cursor_request_position_in_host_;

    scoped_ptr<ui::ViewProp> prop_;

    // The InputMethod instance used to process key events.
    // If owned it, it is created in GetInputMethod() method;
    // If not owned it, it is passed in through SetSharedInputMethod() method.
    ui::InputMethod* input_method_;

    // Whether the InputMethod instance is owned by this WindowTreeHost.
    bool owned_input_method_;

    gfx::Insets output_surface_padding_;

    DISALLOW_COPY_AND_ASSIGN(WindowTreeHost);
};

} // namespace aura

#endif // UI_AURA_WINDOW_TREE_HOST_H_
